The purpose of “Evidence in Practice” is to illustrate how evidence is gathered and used to guide clinical decision making. This article is not a case report. The examination, evaluation, and intervention sections are purposely abbreviated.

A48-year-old woman was referred to our clinic with pain in the lateral epicondyle region of her right elbow. She is right-hand dominant. This pain started about 1 year ago, and the pain gradually increased throughout the past summer. During the warmer months she rides a motorcycle almost every day. The right hand is responsible for controlling the throttle of her motorcycle, and the wrist extensor muscles must contract to maintain active wrist extension for long periods of time. The right hand also controls the front brake lever, which is squeezed to apply the brake. This action also requires that the wrist extensor muscles contract to stabilize the wrist as the finger flexor muscles contract to squeeze the lever. The patient, therefore, uses her right wrist extensors continuously when riding a motorcycle, and these muscles might be overused during frequent or lengthy rides.

For our patient, the duration of a ride depends upon her destination, with trips ranging from 30 minutes to 10 hours a day. During the winter months, the pain subsided. With the weather getting warmer, she resumed riding and was aware of a sudden increase in pain in the posterolateral region of her right elbow. Applying the brake increased her pain immediately. She also noticed increased pain when picking up a coffee mug or carrying groceries in plastic bags. She has tried to manage her pain conservatively with oral nonprescription analgesics and ice massage, but her pain has worsened considerably over the past 2 weeks. She was referred to our clinic after consulting with a physician for possible treatment.

Examination and evaluation:

Examination revealed pain during active wrist extension and passive wrist flexion. Pain was assessed using a 10-cm visual analog scale (VAS), with end points of “no pain” and “worst pain imaginable” on the left and right ends of the scale, respectively.1 She rated her highest level of pain as 7.9 cm, which she describes as occurring after several hours of riding, and her current pain as 3.4 cm. Palpation by the physical therapist (TH) also elicited pain over the lateral epicondyle, especially over the proximal aspect of the extensor carpi radialis brevis muscle. Localized sensitivity to palpation also was noted at the radial head.

Elbow and wrist range of motion (ROM) were measured using a standard goniometer according to the techniques described by Norkin and White.2 Values for ROM were determined to be within normal limits, and these values were as follows:

Elbow extension/flexion: 0–141 degrees

Wrist flexion: 0–74 degrees

Wrist extension: 0–70 degrees

Pronation: 0–75 degrees

Supination: 0–79 degrees

Grip strength was assessed at 90 degrees of elbow flexion using a Jamar hand dynamometer.3,* Three measurements were taken, and the average was recorded. Average grip strength was 60 pounds on the right and 59.3 pounds on the left, with pain elicited over the right lateral epicondyle during measurement of right grip strength.

Based on these findings, we concluded that this patient had lateral epicondylitis, which was most likely caused by overuse of the wrist extensor muscles. We believed that her recent increase in motorcycle riding had aggravated a previous tendinosis in the common extensor tendon and that the sudden recurrence of symptoms suggested an acute inflammatory component to her existing tendinopathy. We therefore decided to implement a treatment program that we use routinely in our clinic for similar cases of lateral epicondylitis. This program included cross friction massage, stretching, progressive resistance exercises of the wrist extensors, and ultrasound (US).

We included US in this program based on the results of a systematic review that found evidence supporting the use of US in treating lateral epicondylitis.4 This systematic review analyzed 23 randomized controlled trials that used various interventions for lateral epicondylitis, including US, electrotherapy, laser therapy, exercises, and mobilization techniques. Two studies in this review compared US with placebo treatment, and the authors of the systematic review were able to pool the results from the 2 studies to determine that US produced significant and clinically meaningful benefits when used to treat lateral epicondylitis. We therefore typically include US as part of our treatment regimen based on this evidence.

Because we would be applying US, we wondered whether the US could also be used to administer a medication, such an anti-inflammatory steroid or nonsteroidal anti-inflammatory drug, transdermally. This technique, commonly known as phonophoresis, has been advocated in certain textbooks and physical therapist education curricula as a method for enhancing the transdermal administration of certain medications.5 We reasoned that an anti-inflammatory medication might help reduce pain and inflammation and thereby allow more aggressive exercise, stretching, and cross friction massage techniques. We were interested in whether the research literature provided evidence to support the idea that phonophoresis is more effective than US in treating conditions such as lateral epicondylitis. If there was supporting evidence, we also wanted to find out what specific medications and treatment variables have been documented in the literature as being beneficial in this condition.

We therefore asked the following questions: Is there evidence that phonophoresis is more effective than US in treating pain associated with lateral epicondylitis? If so, what specific medications and phonophoresis variables have been documented in the literature when using this intervention in people with this condition?

Databases searched:

MEDLINE, CINAHL, Cochrane Database of Systematic Reviews, SPORTDiscus

We searched all 4 databases simultaneously by using the EBSCOhost search engine (ejournals.ebsco.com)† that was available through the library Web site at the college where we work. Details of how to use a similar search engine (Ovid) have been reported previously in another Evidence in Practice article.6 Our search was performed on September 19, 2005.

Keywords:

lateral epicondylitis AND phonophoresis

We decided to select keywords that closely reflected this patient's primary problem (lateral epicondylitis) and the primary intervention that we were considering (phonophoresis). We realized, of course, that this search might fail to retrieve articles that dealt with other treatments of lateral epicondylitis. Our question, however, was whether adding some type of medication to US treatments (phonophoresis) might help decrease pain more than US without any medication. We felt reasonably confident that using these specific keywords would retrieve the articles that were especially germane to our patient.

We performed a search using the keywords “lateral epicondylitis” and “phonophoresis.” This search retrieved 6 citations (Figure). We decided not to review 3 articles: 1 article was a case report (Panus), and 2 articles were reviews or clinical perspectives (Sevier, Sevier and Wilson). We deemed the other 3 articles (Trudel et al, Baskurt et al, Klaiman et al) to be the best evidence because they used some type of experimental design or were systematic reviews. These articles are discussed below, and the relevance of each article to our clinical question is addressed.

Citations retrieved by the search string “lateral epicondylitis AND phonophoresis” in a simultaneous search of the databases MEDLINE, CINAHL, Cochrane Database of Systematic Reviews, SPORTDiscus using the EBSCOhost search engine. Citations in red were selected for further review.

This article was categorized as a systematic review, implying that the authors used specific methods to retrieve and critically analyze pertinent studies in the literature. As indicated in the article, 5 reviewers searched the literature. Their credentials, however, were not described. Specific databases used in these searches were listed as MEDLINE, CINAHL, EMBASE, PEDro, and the Cochrane Database of Systematic Reviews. Search terms (keywords) included a comprehensive list of impairments (tennis elbow, lateral epicondylitis, epicondylalgia) and conservative interventions (eg, US, transcutaneous electrical nerve stimulation, exercise, and so forth). Apparently, “phonophoresis” was not used as a search term, although some of the US studies incorporated drug administration into their intervention. Studies dealing with more invasive treatments (eg, surgery, splints, casts) were excluded, and these searches were limited to only English-language studies, studies on adults (over age 18), studies on humans, and randomized controlled trials (RCTs) or quasi-RCTs. The term “quasi-RCT” was not defined in this article, and we were not sure exactly what criteria the authors used to classify studies by this term.

The searches retrieved 209 studies, but only 31 of these studies were deemed relevant by at least one of the reviewers. These 31 studies underwent closer scrutiny by 2 examiners using a rating system developed by one of authors of the article. The 2 examiners rated the quality of each study's methods and categorized each study according to criteria established by Sackett.7 Seven studies were excluded at this stage because, on closer inspection, they did not fulfill the appropriate criteria, leaving 24 studies for this systematic review.

Regarding US treatment, this article identified 6 studies that incorporated some form of US and were categorized as at least 2b (individual cohort studies and low-quality RCTs) according to Sackett's classification. Only 2 of these studies, however, used phonophoresis as part of their intervention. One study by Stratford et al8 had 4 treatment groups: US alone, US with friction massage, phonophoresis alone, and phonophoresis with friction massage. The systematic review did not specify the drug used during phonophoresis, so we needed to retrieve the original study by Stratford et al from our college library to discover that the drug was hydrocortisone (an anti-inflammatory steroid that was administered as 10% hydrocortisone ointment). Nonetheless, the systematic review categorized this study as 1b (individual RCTs with a narrow confidence interval), and assigned this study a quality score of 41 (out of 48), suggesting fairly good methods and credibility. According to this systematic review, all 4 interventions used by Stratford et al seemed equally effective in decreasing pain. Moreover, this review indicated that Stratford et al recommended that US should be used alone (ie, instead of hydrocortisone phonophoresis) because it is a more cost-effective treatment.

The second phonophoresis study addressed in the systematic review by Trudel et al was conducted by Halle et al.9 According to this systematic review, this study used 4 treatment groups: US, US with 10% hydrocortisone, transcutaneous electrical nerve stimulation, and lidocaine/hydrocortisone injection. All 4 groups also received a home program consisting of an elbow cuff, ice massage, and advice to avoid strenuous activity. This study was categorized as 2b (individual cohort studies and low-quality RCTs), but received only 28 out of 48 points on the quality scale used in this systematic review. According to Trudel et al, hydrocortisone phonophoresis in the study by Halle et al resulted in a significant reduction in pain as measured by the McGill Pain Questionnaire. The reviewers, however, later suggested that at least 2 of the pain indexes on the McGill Pain Questionnaire were significantly improved for each group, and that all 4 pain indexes were improved in the group that received the injection. Again, the summary of this study was confusing, and we needed a copy of the original study from our college library.

The systematic review also addressed other conservative treatments and ultimately concluded that several interventions (eg, acupuncture, exercise therapy, and so forth) had sufficient evidence for producing positive effects based on their design (category 2b or higher according to Sackett) and the quality rating used in this review. Interestingly, the reviewers included phonophoresis in this list of effective interventions despite the fact that neither study addressed in this review showed a clear benefit of adding a drug to the US treatment. The best evidence discovered in this review (Stratford et al8) apparently recommended that phonophoresis should not be used in favor of US, because both interventions produced similar effects and adding the drug only results in an unnecessary cost.

We, therefore, felt that the systematic review by Trudel et al did not provide sufficient evidence for phonophoresis even though the authors of the review support the use of this intervention for lateral epicondylitis. Furthermore, we found their conclusions confusing and misleading. They developed and used a rating scale to assess the quality of these studies, but they did not appear to use this scale to make qualitative judgments about these studies. The study by Halle et al,9 for example, was rated relatively low (28/48), yet the reviewers seemed to accept the results of Halle et al despite its apparent limitations. Consequently, despite the fact that a systematic review is supposed to be one of the highest forms of evidence, we were concerned that the conclusions and recommendations from this review were misleading.

This study is self-described as an RCT, but there is no control group. The researchers treated one group with phonophoresis using a nonsteroidal anti-inflammatory drug (10% naproxen) and treated a second group with 10% naproxen iontophoresis. Both groups had decreased pain, increased grip strength, and improved functional status. The lack of a true control group, however, made it difficult to evaluate the effects of either treatment. For example, we could not be sure that these patients would not improve spontaneously even if there was no treatment. Moreover, this study compared phonophoresis with iontophoresis, but did not provide a direct comparison of phonophoresis with US (ie, the study was not designed to compare the 2 primary interventions that we were considering for our patient). We concluded that this study did not provide evidence that would help us make a clinical decision about whether to include phonophoresis in the treatment regimen.

This was another study that could not be classified as a true RCT because there was no control group. Nonetheless, the design could indicate whether adding a specific drug to the coupling medium during US treatment offers an advantage compared with US used alone. The researchers studied 49 subjects with various musculoskeletal conditions, including 17 subjects with lateral epicondylitis. Other conditions included supraspinatus tendinitis (n=17), De Quervain tenosynovitis (n=4), and inflammation in the biceps tendon (n=3), patellar tendon (n=1), plantar fascia (n=2), or Achilles tendon (n=5). They then paired subjects according to their condition, with one of the pair receiving US and the other subject receiving fluocinonide phonophoresis (US plus 0.05% fluocinonide gel). Fluocinonide is an anti-inflammatory steroid similar to other glucocorticoids such as hydrocortisone and dexamethasone.

Results indicated that patients in both groups improved in pain ratings (measured with a VAS) and sensitivity to pressure over the lateral epicondyle (measured with a pressure algometer). There were no differences, however, in the magnitude of improvement between the groups; that is, adding this anti-inflammatory steroid to the coupling medium did not offer any benefits compared with US used alone. The authors concluded that US can be used to reduce pain and pressure sensitivity in the musculoskeletal conditions observed in this study, but that fluocinonide phonophoresis does not enhance the effects of US.

A primary strength of this study was that treatments were applied in a double-blind fashion. That is, the identical gel was used to apply US and phonophoresis, except that the US gel did not contain fluocinonide, and neither the patients nor the therapist applying the treatment was aware of whether the coupling gel contained the drug. Another strength was the pairing of subjects according to their condition. There were, for example, 17 subjects with lateral epicondylitis, with 9 of these subjects receiving phonophoresis, and the other 8 subjects receiving US.

Another potential strength was the fact that the authors had apparently measured transmissivity of the US gel. They did not, however, report this finding in this article. Without this value, we have no idea whether the US actually penetrated through the gel and into the tissue. This fact, combined with the lack of a control group, limited our ability to interpret these results.

From our perspective, a primary weakness of the study was the fact that only a subset of subjects had lateral epicondylitis. The statistical analysis used in this study did not allow differences to be detected in this subset. The primary outcomes, pain and pressure sensitivity, were analyzed using a 2-way analysis of variance (ANOVA) for repeated measures and a 3-way ANOVA for repeated measures, respectively. These analyses are certainly adequate for analyzing differences over time between the 2 primary groups (US versus phonophoresis) but do not provide insight into whether the subjects with lateral epicondylitis showed differences relative to the 2 larger groups. Furthermore, this study did not report the results according to the subgroups, so we could not make any additional judgments about the effects in only the subjects with lateral epicondylitis. Consequently, the results of this study did not provide evidence that addition of a specific anti-inflammatory steroid (fluocinonide) augmented the effects of US.

Extended search:

Because we did not find conclusive evidence to support the use of phonophoresis in lateral epicondylitis, we were concerned that our search might not be comprehensive enough to find all relevant articles on this topic. We therefore decided to repeat the search using the same databases, but using a somewhat broader term for the intervention. We selected “ultrasound” to make sure that we did not miss any articles that used US as a method for transdermal drug delivery but simply failed to identify this intervention as phonophoresis. We decided to restrict our other keyword to the primary problem (ie, lateral epicondylitis). We again felt that it was important to focus on this impairment because we wanted to keep the search somewhat specific to the treatment of this type of patient rather than the treatment of inflammation at other anatomical sites.

Our search combining the keywords “ultrasound” and “lateral epicondylitis” retrieved 23 citations. We reviewed the titles from each citation, and it appeared that most studies used traditional US without medication to treat lateral epicondylitis. One title, however, suggested that US was used with a coupling medium that contained hydrocortisone.

The abstract indicated that an anti-inflammatory steroid (hydrocortisone) was added to the coupling medium during US treatments to a small sample of people with lateral epicondylitis. This intervention can certainly be considered phonophoresis, but this article was not retrieved during our original search because the authors of this article failed to use the term “phonophoresis” in the keywords or abstract of this article. To understand exactly how this intervention was used in this study, we decided to obtain a copy of the article from our school's library.

This study divided patients into 4 groups: group A (n=9) received conventional US, group B (n=7) received US administered through a coupling medium that contained hydrocortisone (ie, hydrocortisone phonophoresis), group C (n=8) received conventional US and also wore a elbow brace referred to as an “epicondylitis clasp,” and group D (n=12) received hydrocortisone phonophoresis and wore the epicondylitis clasp. As indicated, all patients received some form of treatment; there was no control group for this study. Interestingly, almost all patients had received previous treatment in some form for this condition; only 6 patients reported no previous treatment.

The authors reported that resting pain decreased significantly in group D at the end of the treatment regimen. Resting pain remained essentially unchanged in groups A and C, and increased substantially (32% as calculated from their data) in group B. The authors failed to indicate whether the increase in group B was statistically significant. Their data also suggested that pain during active wrist movements decreased by 31%, 48%, and 40% in groups A, B, and D, respectively, and active pain increased in group B by 37%. Despite these rather substantial changes in pain during active movements, the authors reported that none of these changes were statistically significant. Likewise, no significant effects were seen on the other outcome measures (myometer readings, overall subjective effectiveness) at the end of the treatment regimen.

We found these results difficult to interpret. Substantial changes were seen in certain variables, but these changes apparently failed to reach statistical significance. This failure raises the question of statistical power and the likelihood of a type II error; that is, the number of subjects in each group might have been too small to discover a significant difference in certain variables even though a real difference might have occurred if they included adequate numbers of subjects. The fact that there was no control group raised additional questions about the credibility of these data.

Even with all these limitations, we felt that some evidence might be gleaned from a direct comparison of group A (US) and group B (hydrocortisone phonophoresis). If anything, it appeared that the responses of group B (hydrocortisone phonophoresis) contradicted the responses of the other 3 groups. The subjects in group B apparently experienced more pain at rest and during active wrist movements compared with the other groups, including the subjects that received traditional US (group A). This finding certainly did not support the idea that adding this medication to the US treatments might help decrease pain in our patient. We could not justify the use of phonophoresis in treating our patient based on the results of this study.

Clinical decision:

Based on the available evidence, we did not include phonophoresis in the treatment regimen for our patient. Even though one systematic review (Trudel et al) suggested that phonophoresis might show beneficial effects for lateral epicondylitis, this suggestion seemed inappropriate based on the results from the studies that actually used phonophoresis. The conclusions of the systematic review by Trudel et al did not seem consistent with the results from the individual studies addressed in that review. Furthermore, no strong evidence was presented in any experimental study to suggest that adding a drug to the coupling medium produced additional benefits compared with the use of US alone.

We therefore decided to implement the regimen described earlier—stretching, strengthening, cross friction massage, and US to the right proximal wrist extensor muscle. Pulsed US (20% duty cycle) was administered based on Cameron 5 using a standard coupling gel at a frequency of 3 MHz and an intensity of 1.0 W/cm 2 . In addition to these interventions, we also advised the patient on how to modify to her motorcycle riding style. This advice consisted of maintaining a neutral wrist position at all times. She also was advised to loosen her grip on the throttle to decrease tension as well as stretching her fingers into extension as much as possible on longer rides.